/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.orc;

import org.apache.flink.core.fs.Path;
import org.apache.flink.orc.shim.OrcShim;
import org.apache.flink.table.data.ColumnarRowData;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.data.vector.VectorizedColumnBatch;

import org.apache.hadoop.conf.Configuration;
import org.apache.orc.TypeDescription;

import java.io.IOException;
import java.util.List;

/** {@link OrcSplitReader} to read ORC files into {@link RowData}. */
public class OrcColumnarRowSplitReader<BATCH> extends OrcSplitReader<RowData, BATCH> {

    // the vector of rows that is read in a batch
    private final VectorizedColumnBatch columnarBatch;

    private final ColumnarRowData row;

    public OrcColumnarRowSplitReader(
            OrcShim<BATCH> shim,
            Configuration conf,
            TypeDescription schema,
            int[] selectedFields,
            ColumnBatchGenerator<BATCH> batchGenerator,
            List<OrcFilters.Predicate> conjunctPredicates,
            int batchSize,
            Path path,
            long splitStart,
            long splitLength)
            throws IOException {
        super(
                shim,
                conf,
                schema,
                selectedFields,
                conjunctPredicates,
                batchSize,
                path,
                splitStart,
                splitLength);

        this.columnarBatch = batchGenerator.generate(rowBatchWrapper.getBatch());
        this.row = new ColumnarRowData(columnarBatch);
    }

    @Override
    protected int fillRows() {
        int size = rowBatchWrapper.size();
        columnarBatch.setNumRows(size);
        return size;
    }

    @Override
    public RowData nextRecord(RowData reuse) {
        // return the next row
        row.setRowId(this.nextRow++);
        return row;
    }

    /** Interface to gen {@link VectorizedColumnBatch}. */
    public interface ColumnBatchGenerator<BATCH> {
        VectorizedColumnBatch generate(BATCH rowBatch);
    }
}
